JPS5882321A - Generating circuit for absolute temperature proportional current - Google Patents

Abstract

PURPOSE:To stabilize a current value by eliminating the influence of variation in power voltage upon the difference (VC-VE) between the collector potential and emitter potential of a transistor (TR) as a reference for current generation. CONSTITUTION:The collector of a TRQ4 is connected to the collector of a TRQ3, whose emitter is grounded. The base of the Q4 and that of a Q2 are connected to constitute a common base circuit. The base of a Q7 is connected to the emitter of a Q5, which is connected to the collector of the Q3 at its emitter and also conncted to the common base circuit at its collector. On the other hand, a Q1, Q6, and Q3, Q2 and Q4, and Q7 constitute current mirror circuits respectively. Then, the Q5 and Q4 operate as a starting circuit. At this time, the difference VC-Ve between the collector potential VC of the Q3 and its emitter potential VE is irrelevant to VCC, and the current depends upon only the temperature of the Q3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an absolute temperature proportional current generation circuit that utilizes the phenomenon that the current of a semiconductor element depends on its absolute Y crystal strength.

FIG. 1 is a connection diagram showing a conventional circuit of this type. In the figure, Ql, Q2. Q3. Q5. Q6 is tower/l respectively
, 2nd degree, 3rd degree. Fifth. Each transistor of O6, IJli
j diode, R1, R2, R3, and R4 are resistors, Vcc is a DC power supply, and GND is ground. As shown in the figure, transistors Ql, Q3. Q6U is a transistor with a first polarity, and transistors Q2 and Qs are transistors with a second characteristic. Also, resistor R1, transistor Ql, Q2 . The circuit including the resistor R2 is tentatively referred to as the first circuit, and the circuit including the transistor Q5 and the resistor R4 is collectively referred to as a third circuit. The bases of transistors Ql, Qs, and Qs are connected in parallel, and this is called a common pace circuit.

The anode of diode DI is connected to the base of transistor Q2.

When a DC power supply Vcc is connected to this circuit, ■Cc→R3
→ Base of Q3 → Base of Q5 → R4 → GND current flows and Qs turns on, Vcc −+ Collector of Qs → Base of Q5 → Base of Q3 → Collector of Q3 → D
1→GND current flows, Qs turns on, the base of Q2→R2 current flows, Q2 turns on, current flows to the base of Q6, Q6 turns on, and Ql turns on. In this state, transistor Q2 and diode Di
Configure a current mirror.

Let the collector current of the transistor Q3 be kI, its collector current be Vc, the emitter voltage 1 be VE, and the anode potential of the diode Di be kVF, then Vc = V
cc-R3I, Vg = Vr to Vc-VE: V
c c ((3I - Vp, ., Current ■ is determined by the relationship tt+. VF is kept almost constant because Di forms a current mirror with Q2, but when Vcc changes, Equation (1) Vc Vg varies according to the relationship.

The generally known early effect (E) of transistors
Due to early effect), when the (Vc-VE) of the transistor changes, the collector voltage and current also change.

That is, since the current I varies not only due to the absolute temperature of the transistor Q3 but also due to variations in Vcc, there is a drawback that it is difficult to obtain a stable current.

This invention was made in order to eliminate the above-mentioned drawbacks in conventional circuits, and aims to provide a circuit in which V(!VE) of a transistor, which is a reference for current generation, is not affected by fluctuations in power supply voltage. The purpose is

The present invention will be explained in detail below with reference to the drawings.

FIG. 2 is a block diagram showing one embodiment of the present invention.
The same reference numerals as in the figures indicate the same or corresponding parts and operate in the same way. Q4 is the fourth transistor of the second polarity, Ql is the
It is an off transistor with a polarity of .

The collector of transistor Q4 is connected to the collector of transistor Q3, and its emitter is connected to ground. Resistor R3, transistor Q3. The circuit of Q4 is temporarily called the second circuit, and the base of Q4 and the base of Q2 are connected to form the second circuit.
The base of transistor Q7 is connected to the emitter of transistor Q5, the emitter is connected to the collector of transistor Q3, and the collector is connected to a second common base circuit. Transistor Ql.

Q6 (!:I- The transistor Q3 constitutes a current mirror, and the transistor Q2 and the transistor Q4
rQ7 constitutes a current mirror. Q”+Q4vC
The third circuit constructed in this way operates as a starting circuit in the same way as in the case of FIG. 1.

The collector potential of Qs is Vc, and its emitter potential VE
The pace emitter voltages of Qs, Qs, and Ql are respectively VBE(Qs)I VBE(Qli)l VB
g(Ql) then V, -vBE(q7) -”E
``BE(Qs) - vBE(Qs) but vB[Q
s)=vBE(Qs)"vBE(Li2)""CAl(D"'CVc-VE key VBg(qs)-t21 The value of Vc-VE does not depend on Vcc and is always -VBE(
Qs) (same as "IIE(Qs) or -■B06,7,"), so the current ■ is the same as transistor Q3
It is determined only by the temperature of

Further, the circuit of FIG. 2 has the advantage that Ql is the only element that is substantially increased compared to the circuit of FIG. 1, and since the transistor Q7 is a normal PN junction element, it can be easily integrated into an integrated circuit.

Further, the same operation occurs when R1 and R3 are short-circuited in FIG. 2.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing a conventional circuit, and FIG. 2 is a connection diagram showing an embodiment of the present invention. Ql...Ol transistor, Q2...second transistor, Qs...third transistor, Q4...
Fourth transistor, Qs...fifth transistor,
Q6...O6 transistor, Ql...Off transistor. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Tsutomu Kuzuno - (7) Figure 1

Claims (1)

[Claims] The collector of the transistor with the opposite polarity is connected to the collector of the second transistor with the second polarity, and the emitter of the transistor with the polarity is connected to the DC power supply via the resistor. the collector of the third transistor of the first polarity is connected to the collector of the fourth transistor of the second polarity, and the third transistor a second circuit configured by connecting the emitter of the fourth transistor to the DC power supply via a resistor and grounding the emitter of the fourth transistor, and connecting the collector of the fifth transistor of the second polarity to the DC power supply; A 30th circuit configured by connecting the emitters to the ground through all the resistors, an 30th common base circuit in which the bases of the 1st, 3rd, and 5th transistors are connected in parallel; a second common base circuit connecting the bases of the second and fourth transistors, and having the polarity of the above-mentioned transistors, its emitter is connected to the common base circuit of the above-mentioned '171, its collector is grounded, and its base is connected to the above-mentioned second common base circuit; 6 transistors are connected to the collectors of the transistors of 6 and 6, respectively, and their emitters are connected to the collectors of the third transistors, their collectors are connected to the second common base circuit, and their bases are connected to the second common base circuit, and their emitters are connected to the collectors of the third transistors. Absolute 71 tJJ with off transistors connected to the emitters of the 5 transistors, respectively.
jProportional current generation circuit.